The information commissioner has questioned why the government failed to keep track of whether it had implemented recommendations on improving the safety of “vulnerable” disabled people that had been made in its own secret reports into benefit-related deaths.

Elizabeth Denham said the failure of the Department for Work and Pensions (DWP) to keep track of its actions on “such sensitive cases” was “highly unusual”.

DWP has told her that it has no idea whether it implemented the 10 recommendations.

Last May, following a 21-month battle with Disability News Service (DNS) to keep them secret, DWP was forced to publish 49 heavily-redacted internal “peer reviews”, each of which had been carried out following the death of a benefit claimant.

Many of the reviews – which took place between February 2012 and August 2014 – had included recommendations for improvements in national policies and procedures, in order to avoid future deaths.

Following their publication, DNS asked DWP whether it had implemented 10 particular recommendations for national improvements that related to “vulnerable” benefit claimants and had been included in the peer reviews.

One recommendation was for a review of the employment and support allowance process to help identify vulnerable customers; another called for “a re-launch to staff of the importance of identifying vulnerable claimants and taking their needs into account throughout the whole process”.

A third recommendation was for DWP to consider if claimants with mental health conditions should be considered for a safeguarding visit if they were thought to be at risk, were about to have their benefits removed, and the DWP “decision-maker” had been unable to contact them via telephone.

DWP told DNS last year that it was “not possible” to say if it had implemented the 10 recommendations.

Now, following a complaint submitted by DNS to the Information Commissioner’s Office (ICO) about this failure to provide this information, DWP has told ICO that it has destroyed records relating to how these recommendations were passed to and from the relevant national “customer journey teams”.

It has also told ICO that there was “no requirement” for the department to keep track of what action was taken after these recommendations were passed on.

And it argues that because the peer reviews were a “voluntary internal process”, it had no legal duty to keep this information.

It has told ICO that it has searched its centrally-held files but has failed to find the information sought by DNS.

In a letter to DNS, the ICO says: “DWP has explained that records concerning these communications were not retained and no requirement was in place to track subsequent actions taken.”

The letter adds: “Whilst she does find the lack of requirement for confirmation of action highly unusual following a peer review of such sensitive cases, [the commissioner]is not in a position to issue a decision that DWP should have required feedback in these cases.”

ICO is now writing again to ask DWP to carry out a wider search of its records, something it has so far refused to do.

A DWP spokeswoman said she was unable to comment because the appeal was ongoing.